Buggy code:
public class BillForm extends JFrame { private JButton jButton1 ; private JDatePickerImpl datePicker ; private JLabel title ; private JLabel idShower ; private JLabel nameLbl ; private JTextField clientName ; private JTextField declarate ; private JLabel sonLbl ; private JTable contentTable ; private JLabel nitLbl ; private JTextField clientNit ; private JLabel bsLbl ; private JLabel totalLbl ; private JTextField totalAmount ; private JPanel contentPane ; public static void main ( String [ ] args ) { } public BillForm ( ) { } private void initComponents ( ) { setTitle ( "Liquid" ) ; setSize ( 700 , 500 ) ; setResizable ( false ) ; setLocationRelativeTo ( null ) ; setDefaultCloseOperation ( WindowConstants . EXIT_ON_CLOSE ) ; contentPane = new JPanel ( ) ; contentPane . setBorder ( new EmptyBorder ( 5 , 5 , 5 , 5 ) ) ; setContentPane ( contentPane ) ; contentPane . setLayout ( null ) ; UtilDateModel model = new UtilDateModel ( ) ; Properties p = new Properties ( ) ; p . put ( "text.today" , "Today" ) ; p . put ( "text.month" , "Month" ) ; p . put ( "text.year" , "Year" ) ; JDatePanelImpl datePanel = new JDatePanelImpl ( model , p ) ; datePicker = new JDatePickerImpl ( datePanel , new DateLabelFormatter ( ) ) ; title = new JLabel ( "FACTURA" ) ; title . setFont ( new Font ( "Arial" , Font . PLAIN , 40 ) ) ; idShower = new JLabel ( "Nº<seq2seq4repair_space>000001" ) ; idShower . setFont ( new Font ( "Courier<seq2seq4repair_space>New" , Font . PLAIN , 20 ) ) ; nameLbl = new JLabel ( "Señor(es)" ) ; clientName = new JTextField ( ) ; nitLbl = new JLabel ( "NIT//C.I." ) ; clientNit = new JTextField ( ) ; String [ ] columnNames = new String [ ] { "Cod" , "Cant." , "Unidad" , "Descripcion" , "Precio<seq2seq4repair_space>Unit." , "Importe" } ; Object [ ] [ ] tempData = new Object [ ] [ ] { new Object [ ] { "00126" , 20 , "Kg." , "Electrodo<seq2seq4repair_space>7018<seq2seq4repair_space>1//8" , 22.8 , 0 } , new Object [ ] { "00119" , 20 , "Kg." , "Electrodo<seq2seq4repair_space>6013<seq2seq4repair_space>1//8" , 22.8 , 0 } } ; contentTable = new JTable ( tempData , columnNames ) ; contentTable . setFont ( new Font ( "Arial" , Font . PLAIN , 20 ) ) ; contentTable . setRowHeight ( 25 ) ; contentTable . getColumnModel ( ) . getColumn ( 0 ) . setPreferredWidth ( 60 ) ; contentTable . getColumnModel ( ) . getColumn ( 1 ) . setPreferredWidth ( 40 ) ; contentTable . getColumnModel ( ) . getColumn ( 2 ) . setPreferredWidth ( 50 ) ; contentTable . getColumnModel ( ) . getColumn ( 3 ) . setPreferredWidth ( 280 ) ; contentTable . getColumnModel ( ) . getColumn ( 4 ) . setPreferredWidth ( 70 ) ; contentTable . getColumnModel ( ) . getColumn ( 5 ) . setMinWidth ( 20 ) ; contentTable . setAutoResizeMode ( JTable . AUTO_RESIZE_LAST_COLUMN ) ; JScrollPane tablesp = new JScrollPane ( contentTable ) ; calculateEachArticlePrice ( 1 , 4 , 5 ) ; totalLbl = new JLabel ( "Total" ) ; totalAmount = new JTextField ( ) ; double total = 0 ; for ( int i = 0 ; i < ( contentTable . getRowCount ( ) ) ; i ++ ) { total += Double . parseDouble ( contentTable . getModel ( ) . getValueAt ( i , 5 ) . toString ( ) ) ; } totalAmount . setText ( String . valueOf ( total ) ) ; sonLbl = new JLabel ( "Son:" ) ; declarate = new JTextField ( ) ; bsLbl = new JLabel ( "Bolivianos" ) ; jButton1 = new JButton ( ) ; jButton1 . setText ( "PRINT" ) ; title . setBounds ( 270 , 30 , 200 , 30 ) ; datePicker . setBounds ( 300 , 80 , 150 , 30 ) ; idShower . setBounds ( 500 , 80 , 160 , 30 ) ; nameLbl . setBounds ( 40 , 120 , 140 , 30 ) ; clientName . setBounds ( 100 , 120 , 350 , 30 ) ; nitLbl . setBounds ( 460 , 120 , 60 , 30 ) ; clientNit . setBounds ( 510 , 120 , 150 , 30 ) ; tablesp . setBounds ( 30 , 160 , 640 , 200 ) ; sonLbl . setBounds ( 40 , 390 , 50 , 30 ) ; declarate . setBounds ( 70 , 390 , 350 , 30 ) ; totalLbl . setBounds ( 540 , 360 , 50 , 30 ) ; totalAmount . setBounds ( 570 , 360 , 100 , 30 ) ; bsLbl . setBounds ( 425 , 390 , 70 , 30 ) ; <START_BUG> jButton1 . setBounds ( 580 , 420 , ( - 1 ) , 30 ) ; <END_BUG> contentPane . add ( title ) ; contentPane . add ( datePicker ) ; contentPane . add ( idShower ) ; contentPane . add ( nameLbl ) ; contentPane . add ( clientName ) ; contentPane . add ( nitLbl ) ; contentPane . add ( clientNit ) ; contentPane . add ( tablesp ) ; contentPane . add ( sonLbl ) ; contentPane . add ( declarate ) ; contentPane . add ( totalLbl ) ; contentPane . add ( totalAmount ) ; contentPane . add ( bsLbl ) ; contentPane . add ( jButton1 ) ; } public static void setStyle ( ) { } public void calculateEachArticlePrice ( int qValueCol , int upValueCol , int resValueCol ) { } }

Fix:
jButton1 . setBounds ( 580 , 420 , 80 , 30 ) ;